With the increasing awareness of people's health care, people's natural requirements for the medical environment is also correspondingly increased for modern medical building builders, to create ecological health care green hospitals has become the direction of our efforts, the introduction of green energy-saving ground-source heat pump technology in modern hospital buildings, so that the hospital has become a truly harmonious and comfortable, beautiful environment, green ecological modern convalescence place. Therefore, ground source heat pump system has great application value in modern hospital buildings, and it will become one of the key technologies to be promoted in the field of energy saving of hospital buildings in China.
With the rapid development of the national economy, people's health care awareness is increasing, the requirements of the medical environment is also correspondingly increased, to create ecological health care green hospitals has become the direction of our efforts. Therefore, in the project, planning and design of modern hospital, we should combine the new concepts of human life science, ecology and environmental science to introduce the green and energy-saving ground source heat pump technology into the modern hospital building, so as to improve the air quality of the hospital, optimize the circulation of the hospital's airflow, reduce the hospital's energy consumption, and expand the hospital's green coverage, so as to make the hospital become a truly harmonious, comfortable, beautiful environment and green ecological modern convalescent place. modern convalescent place.
1. The working principle of ground source heat pump technology
1.1 What is ground source heat pump
Ground source heat pump system, also known as ground source central air conditioning, is a system that utilizes shallow and deep earth energy, including soil, groundwater, surface water and other natural energy sources as heat source in winter and cold source in summer, and then supply cooling and heating to the building by heat pump unit, i.e. natural energy source that is, natural energy, is upgraded to a kind of energy-efficient thermal system for building energy after a reverse thermal cycle. Ground source heat pump system, is a new type of central air conditioning system that utilizes renewable energy for both heating and cooling.
1.2 System Composition and Classification
Ground-source heat pump system, usually consists of three parts: the geothermal energy exchange system, the heat pump room system, and the end heat exchange system in the building. We can be divided into two parts according to the installation location (installation site) above ground (indoor) and underground (outdoor), and the above ground part is mainly composed of HVAC equipment. The underground part is also known as underground coupling system or underground heat exchanger, and there are 3 forms of more applications: open loop system, closed loop system, and hybrid loop system. Ground source heat pump system can be divided into surface water ground source heat pump system, buried pipe ground source heat pump system, groundwater ground source heat pump system according to the different ground heat energy exchange system (Figure 1).
Figure 1 Ground Source Heat Pump System
2. Application of Ground Source Heat Pump Technology in Hospital Buildings
2.1 Energy Efficient and Green
The ground source heat pump system dissipates heat at high temperature difference in summer and extracts heat at low temperature difference in winter, which makes the heat exchange efficiency of the underground part of the system is very high, so that it only needs a small-power compressor when generating the same amount of heat or cold. Realization, and winter operation does not require any auxiliary heat source and defrosting system, greatly reducing the consumption of electricity and air conditioning host defrosting energy loss, so as to achieve the purpose of air conditioning host energy saving, compared with the boiler (electricity, fuel) heating system, boiler heating can only be more than 90% of the electrical energy or 70-90% of the internal energy of the fuel is converted into heat for the user's use, so the ground-source heat pumps to be more than an electric boiler heating Saving more than two thirds of electric energy, saving more than one half of energy than fuel boiler; at the same time, ground source heat pump system neither destroys groundwater resources, nor any pollution, can be constructed in the densely populated modern medical area, no combustion, no smoke exhaust, no any gas emission to the atmosphere, and no waste, i.e., no pollutant emission, no noise and mold contamination, and do not need to pile up fuel waste in the Site, and do not have to transport heat over long distances, can significantly reduce greenhouse gas emissions, not only to protect the environment, but also can greatly reduce the greenhouse effect, slowing down the process of global warming, is an ideal energy saving, environmentally friendly "green technology".
2.2 Stable and reliable operation of the unit
The heat and cold source of the ground source heat pump system is the ground, and the temperature of the ground is relatively stable throughout the year, far less than the ambient air temperature fluctuations, higher than the ambient air temperature in winter, lower than the ambient air temperature in summer, the temperature fluctuation range is generally 10 ℃ ~ 25 ℃, especially in the case of such modern hospitals as the new hospital in Zhejiang Province, in the wetlands of the island in Zhejiang Province. Wetlands within the island, warm in winter and cool in summer, has a unique resource advantage, ground source heat pump system is a good source of cooling and heating; at the same time, due to the constancy of the temperature, so that the system's compressor work is stable, will not appear in the traditional equipment refrigerant pressure is too high or too low phenomenon, the operation of more stable. In the system unit design and configuration, each unit adopts a relatively independent cooling or heating system, as long as the buried piping system operates normally, the failure of individual unit will not affect the operation of the whole system. The operating condition of the unit is stable, almost unaffected by changes in ambient temperature, even in the cold winter heat production will not be attenuated, not to mention the phenomenon of shutdown due to frost defrosting, even if the system is in the cold winter, the unit can be a steady stream of heating to the wards, outpatient clinics and other users. Due to the stable working condition of the system, it is possible to design a simple system with fewer parts, simple and reliable operation of the unit, low maintenance costs; high degree of automatic control, unattended; in addition, the unit has a long service life, according to foreign statistics, the unit life is more than 20 years.
2.3 Reduce construction and labor costs
Input ground source heat pump system without cooling towers, boiler rooms and other ancillary rooms, eliminating the boiler room, cooling towers and ancillary oil tanks, coal yards, slag place occupied by the valuable area, saving the building space and the hospital land, reducing the land cost of hospital buildings, generating additional economic benefits, and improve the external image of the environment. Save boiler room, save boiler duty and maintenance personnel, greatly saving the hospital's labor costs, eliminating the boiler room heating noise pollution, smoke and dust hazards and other concerns, in line with the modern hospitals to reduce energy and emissions, reduce staffing and reduce consumption, efficient operation of the logistical reform of the development trend. At the same time, the ground source heat pump system eliminates the boiler room and oil storage and other hazardous facilities, eliminating a great deal of safety hazards in modern hospitals, and is a favorable condition for the creation of safe hospitals.
3. Economic Benefit Analysis
Since the heat source temperature of ground source heat pump is more stable throughout the year, generally 10℃～25℃, its cooling and heating coefficient can be up to 3.5～4.4, which is about 40% higher compared with the traditional air source heat pump, and its operation cost is 50%～60% of the common central air conditioner. Maintenance is minimal, the service life and the same period of the building, depreciation and maintenance costs are also much lower than traditional air conditioning. In the cost of the project, the cost of underground piping project accounts for about one-third of the total cost of the system engineering. It is estimated that the initial investment in the ground source heat pump system than ordinary heat pump unit to be larger, about two times the ordinary cost, but in the operating costs have a greater advantage, according to the U.S. Environmental Protection Agency (EPA) estimates that the soil source heat pump system operating costs than the air-cooled heat pump operating costs savings of 30% to 40%, which is mainly in the host of the operating efficiency can be reflected. Ground source heat pump system is not only multi-purpose, but also can replace the original boiler plus chiller two sets of devices or systems, not only saves a lot of energy, but also reduces the initial investment in equipment. At the same time the system is compact, eliminating the boiler room and cooling tower, saving building space, but also conducive to the aesthetics of the building. As mentioned above, another significant feature of the ground source heat pump system is that it greatly improves the utilization of primary energy, and therefore has the advantage of high energy efficiency, which is about 40% to 60% more efficient than the operation of traditional air conditioning systems. In addition, the more constant temperature of the ground source makes the heat pump unit run more reliably and stably, and the maintenance cost of the whole system is greatly reduced compared with the boiler-air-conditioning system, which ensures the high efficiency and economy of the system.
Conclusion
While the application of ground source heat pump technology has not been long, the basic research and practical experience in hospital buildings in China is still insufficient, so some of the contents can only be quoted from foreign literature. But I believe that with the further guidance of the national policy, the continuous development of ground source heat pump technology and further improve the maturity of its full use of underground heat resources in the ecological and environmental protection advantages will be more significant, the application of this technology in our country will become more and more widespread. For the pursuit of green ecological modern hospital builders, ground source heat pump system has great application value, I believe that in the near future it will become one of the key technologies to promote the field of energy saving in China's hospital buildings.
The above is collected and organized by Zhongda Consulting
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